In a large bowl, whisk together all the marinade ingredients until well combined. Add the chicken thighs to half of the marinade. Reserve the other half of the marinade in the refrigerator for later use. Cover and refrigerate the coated chicken for at least 4 hours or overnight.
Set your oven to 400°F. Line a baking sheet with parchment paper or aluminum foil for easy cleanup. Place the marinated chicken thighs on the prepared baking sheet (with a baking rack on top for a glossier finish), shaking off excess marinade. Bake for 25-30 minutes, flipping halfway through.
For a deeper caramelization, baste with the reserved marinade mixture during the last 5-7 minutes.
For that authentic char siu look, switch the oven to broil and cook for an additional 2-3 minutes until slightly charred. Keep a close eye to prevent burning.
Let the chicken rest for a few minutes before slicing. Serve with steamed rice, stir-fried vegetables, or in a noodle dish for a complete meal.
